The present invention relates to folding multipurpose tools, and in particular to such a tool which may include a pair of pliers and several different tool bits and blades and that can be folded small enough to be carried comfortably in one's pocket.
Folding knives and the like including blades or tool bits available to be unfolded from both ends of a handle have typically included springs in the back of the handle to hold each blade in its folded position or in its deployed position by pressing on the base of the blade. Not only do such springs press against the base of a blade to hold it open or closed, but they also bear a considerable axially-directed load when a deployed blade or tool bit is used. For example, a knife acts as a lever tending to rotate about its pivot pin and a surface on the rear of the knife blade presses against an end of the spring.
Where a single spring is required to act upon tool members on both ends of a handle the spring has typically been held in place with respect to other parts of the handle by a rivet located centrally along the length of the handle.
The forces generated by use of a knife blade typically are fairly small, and small-diameter blade pivot pins and spring-holding fasteners are sufficient. Where pliers are supported by a pair of folding handles, however, the loads to be carried axially within a spring are potentially significantly greater. A rivet or other fastener holding or supporting a spring in a handle of such a tool would need to be larger, and a spring would need to have a correspondingly large area to receive such a fastener. For a tool including folding pliers and intended to be small enough to be carried in one's pocket, that type of construction would result in an undesirably large tool.
Folding multipurpose tools of many types have been available in recent years, but most such tools including pliers large enough to be fairly strong are rather bulky, heavy, and industrial in appearance. Manufacture of more compact tools, using a single spring for multiple blades, has required careful adjustment during assembly in order to have pliers jaws and other blades and tool bits fold and extend crisply and without undesirable amounts of free play or friction. Use of an individual spring for each blade or bit has resulted in loss of compactness, making a tool requiring a pair of handles undesirably bulky. Smaller tools including folding pliers have been comparatively weak and thus of limited utility.
In some previously available multipurpose tools including folding pliers, various tool blades are available only after having to separate a pair of handles to reach those tool blades.
What is desired, then, is a multipurpose folding tool having a pleasant appearance, which has adequate strength, which can be folded or opened easily yet which feels secure, which can be manufactured satisfactorily without extremely close tolerances, and yet which is light enough and compact enough when in a folded configuration to be carried comfortably in one's pocket.